If I have to choose between three
things, do I have three choices?
Yes, in my experience "choice" is widely used in this context.
I
have always thought of a "choice" as
being either the act of choosing or
the result of said choosing, but not
one of the options from which to
choose.
Really? If I google for "you have three choices" I find 700,000 results.
If someone tells me I have two
choices, I tell them "No, I have one
choice. I have two options." Am I
right?
I'm not familiar with this particular rule, but it sounds like pedantry to me, especially since the way you frame the question makes it seem like many people are saying "choice" rather than "option" to you, and so you must already be aware that "choice" meaning "option" is a common usage.